Android captured a leading 44 percent of all mobile app downloads in the second quarter, according to ABI Research, surpassing Apple's iOS, which grabbed 31 percent.
The research firm attributed Android's gain in part to recent shipment numbers.
For the second quarter, growth in iPhone shipments fell to 9 percent from 15 percent in the first quarter, while Android's shipment growth rose to 36 percent from 20 percent. Android's total install base now outweighs that of iOS by a factor of 2.4 to 1, ABI said, a ratio that will reach 3 to 1 by 2016.
But Android's open-source strategy is also driving app downloads, according to ABI.
"Being a free platform has expanded the Android device install base, which in turn has driven growth in the number of third party multi-platform and mobile operator app stores," ABI research associate Lim Shiyang said in a statement. "These conditions alone explain why Android is the new leader in the mobile application market."
But though Android may be tops in total downloads, Apple still holds the lead in the number of downloads per user.
"Despite leading in total mobile application downloads, Android's app downloads per user still lag behind Apple's by 2-to-1," Dan Shey, ABI's practice director for mobile services, said in a statement. "Apple's superior monetization policies attracted good developers within its ranks, thus creating a better catalog of apps and customer experience."
Overall, the number of mobile app downloads across the world is expected to hit 29 billion in 2011, up from only 9 billion last year. That's due in large part to the surge in demand for smartphones, which are likely to see their customer base grow by 46 percent this year, added ABI.
A recent look into the crystal ball from research firm Berg Insight sees the number of mobile app downloads reaching 98 billion in 2015. A June report from In-Stat was more cautions, eyeing just 48 billion in another four years.